March 2019

“Larger, prospective studies would be needed to confirm our results that the etiology of glaucoma plays a role in XEN surgery outcomes and to ascertain whether secondary glaucoma might be associated with surgical complications.”
—Nuno Moura-Coelho, MD

Superior performance was observed with the XEN 45 Gel Stent in primary open angle glaucoma eyes over a 12-month period, according to new study data

The results of a new 12–month study1 seem to indicate that the etiology of glaucoma may influence the outcomes of XEN 45 Gel Stent (Allergan, Dublin, Ireland) implantation surgery in glaucoma patients. Individuals with primary open angle glaucoma showed a higher benefit 1 year after surgery than those with secondary open angle glaucoma, according to Nuno Moura–Coelho, MD, ophthalmology department, Central Lisbon Hospital Center, faculty of medical sciences, NOVA Medical School, Lisbon, Portugal, who presented the as yet unpublished study data in a talk he held on behalf of his study group at the 36th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS).
“Although it is well known that the XEN stent reduces IOP and the need for pressure-reducing medications in open angle glaucoma, it is still unknown whether the type of open angle glaucoma influences or is a determinant of the long–term outcomes of XEN stent implantation. In our study, the XEN stent appears to have higher efficacy in IOP reduction in primary open angle glaucoma patients when compared with secondary open angle glaucoma patients,” Dr. Moura–Coelho said in his presentation.
The XEN 45 microinvasive surgical device is an FDA–approved implant for medically refractory open angle glaucoma (mrOAG). It has demonstrated its effect on IOP lowering and medication reduction in open angle glaucoma patients, with a good safety profile, in a number of publications.2,3

Study design and outcomes

Dr. Moura–Coelho’s study compared the safety and efficacy 1 year after implantation of the XEN 45 Gel Stent between eyes with medically refractory primary open angle glaucoma (POAG) and secondary open angle glaucoma (SOAG). The study was conducted at the ophthalmology department of Central Lisbon Hospital Center and reports the initial experience with XEN implantation nationwide.
The retrospective interventional case series included 19 eyes of 18 patients with mrOAG who underwent XEN implantation. The patients were grouped into two groups according to glaucoma etiology: POAG/PG and SOAG/SG.
The primary outcome measure was success at the 12–month follow–up exam, which was defined as an IOP reduction rate (IOP–RR) of greater than or equal to 20% from baseline and an IOP of less than or equal to 18 mm Hg and above 5 mm Hg, with the need for IOP–lowering drugs (qualified success) or without the need for drugs (complete success), and without reoperation for glaucoma including needling. The secondary outcome measures included IOP reduction, IOP–RR, reduction in the number of IOP–lowering drugs, and complications.
At 12 months post–XEN implantation, Dr. Moura–Coelho observed a significant IOP reduction in the PG group (10 mm Hg, p=.006), as well as a lower median number of drugs (–3, p=.003). The difference was not significant in the SG group (–2 mm Hg, p=.069). Median IOP reduction and IOP–RR were significantly higher in the PG group compared with the SG group (p=.039 and .039, respectively). Dr. Moura–Coelho noted that the differences between the patient groups for achieving success and in the number of complications were not statistically significant (p=.208 and .209, respectively).

Limitations

According to Dr. Moura–Coelho, the study’s limitations include: the small sample size, univariate analysis, and the non–randomized, single center, retrospective study design.
“The absolute number of successful cases was higher in PG eyes and eyes requiring additional surgeries were lower in this group as well compared to eyes with SG. Larger, prospective studies would be needed to confirm our results that the etiology of glaucoma plays a role in XEN surgery outcomes and to ascertain whether secondary glaucoma might be associated with surgical complications,” Dr. Moura–Coelho said.